COSMETIC COMPOSITION FOR ARTIFICIAL TANNING OF THE SKIN

Abstract: An artificial tanning product comprising one or more compositions containing, separately or together, a cosmetically effective amount of dihydroxyacetone (DHA) as an artificial tanning agent, and one or more iron salt or salts. The iron salts can be any ferrous or ferric salts for example nitrate, gluconate or citrate. A method of applying the tanning product is also disclosed comprising application of an iron salt composition optionally further comprising a moisturiser in conjunction with separate or simultaneous application of a tanning composition comprising DHA.

Description: Cosmeti c composi ti on for arti fi ci al tann i ng of the ski n . The present invention relates to compositions that produce tanned skin in the absence of UV radiation in particular to those comprising dihydroxyacetone as the tanning agent . Known artificial tanning compositions use the artificial tanning agent dihydroxyacetone of the following formula : - O II HO — CH 2 — C— CH 2 — OH I (referred to hereinafter as 'DHA'). The term 'artificial tanning agent' is used hereinafter to denote an agent which acts on the skin to produce a skin tan without requiring ultra-violet radiation (UV) . This is in contrast with agents that act to accelerate the natural tanning processes that occur when skin is exposed to UV. DHA reacts with the amino acids and amino groups of keratin proteins present in the outer layers of the skin epidermis, to form brown-coloured compounds. The reaction is believed to be similar to the Malliard reaction (non-enzymic browning) in which reducing sugars react with amino acids, peptides and proteins to form compounds containing amino and carbonyl functionality, these compounds being polymerised to brown melanoidines. Artificial tanning agents have the advantage of producing a skin tan without the need to expose the skin to UV radiation. The increasing tendency of people to sunbathe by exposing skin for long periods to UV radiation from sunlight or sunlamps in order to produce a skin tan, has led to an increase in the incidence of skin cancer worldwide, particularly amongst fair skinned people. Depletion of atmospheric ozone has also increased the intensity of UV radiation reaching the earth particularly at higher latitudes. Thus, the use of artificial tanning agents to produce tanned skin is increasingly advantageous, not only in less sunny climates, but in sunny climates as an alternative or supplement to exposure of the skin to UV radiation. Current artificial tanning compositions comprising DHA are not completely satisfactory. The skin colour produced by a DHA composition is a yellow-brown which can look unnatural especially on fair skin. As DHA takes several hours to develop colour on the skin, it can be difficult to apply the DHA tanning composition evenly over the skin, which can result in a streaky appearance. The colour cannot be washed off, but fades as the upper layers of the epidermis wear away. It is an object of the invention to provide an artificial tanning product comprising DHA, which produces a more natural colour, that is a less yellow coloured, artificial tan, and which develops colour more rapidly so as to be more easy to apply as an even coat on the skin to avoid streaking, compared to known artificial tanning products comprising DHA. It has been discovered that in the presence of iron salts, DHA produces an artificial tan less yellow in colour. The mechanism of action may be formation of complexes between iron and DHA (or its reaction products) acting as a ligand. The presence of iron also causes an immediate pale colour to be produced when the DHA is initially applied to the skin, thus aiding application in an even layer to avoid a streaky appearance. After a few hours this pale colour darkens to give the final darker colour. The present invention comprises an artificial tanning product comprising one or more compositions containing, separately or together, a cosmetically effective amount of dihydroxy acetone as an artificial tanning agent and one or more iron salt or salts. If the product comprises two or more compositions these may be packaged in a single pack comprising two or more parts . The amount of DHA present in one or more composition or compositions comprising the present invention may be formulated to suit light, medium or dark skin types, preferably in an amount from about 0.1% to about 10%, more preferably from about 1% to about 7%, most preferably from about 2% to about 5% by weight of that composition. The iron salt or salts can be any ferrous or ferric iron salt for example nitrate, giuconate or citrate. Preferably, the iron salt or salts are present in one or more of the composition or compositions of the product of the invention in an amount from about 0.1% to about 20%, more preferably from about 0.5% to about 10%, most preferably from about 1% to about 5% by weight of that composition. Particularly good results are obtained when using ferric salts in combination with a DHA tanning composition, to produce an artificial tan of less yellow tone, than produced by a DHA tanning composition alone. Sunscreening agents may be incorporated into any of the composition or compositions comprising the present invention. The term 'sunscreening agent' is used herein to encompass any ingredient or ingredients used in tanning lotions, sunscreens and sunblockers or the like, which are intended for use on the body to provide protection against UV radiation produced from the sun or other artificial sources. Examples of suitable sunscreening agents include:- a) titanium dioxide; b) p-aminobenzoic acids, esters and derivatives thereof, such as 2-ethylhexyl p-dimethylaminobenzoate; c) methoxycinnamate esters such as 2-ethylhexyl p-methoxycinnamate, 2-ethoxyethyl p-methoxycinnamate or α, β-di- (p-methoxycinnamoyl ) -α' - (2-ethylhexanoyl) glycerin; d) benzophenones such as oxybenzone; e) dibenzoylmethanes; f) salicylate esters; g) zinc oxide; and h) mixtures thereof. Any sunscreening agent may be present in any of the composition or compositions comprising the present invention in an amount from about 0.1% to about 20% by weight of that composition. Any of the composition or compositions comprising the present invention may be a gel. Any of the composition or compositions comprising the present invention may include either oil-in-water or water-in-oil emulsions. The oil phase of emulsions comprising the present invention may include for example: a) hydrocarbon oils such as paraffin or mineral oils; b) waxes such as beeswax or paraffin wax; c) natural oils such as sunflower oil, apricot kernel oil, shea butter of jojoba oil; d) silicone oils such as dimethicone, cyclomethicone or cetyldimethicone; e) fatty acid esters such as isopropyl palmitate or isopropyl myristate; f) fatty alcohols such as cetyl alcohol or stearyl alcohol; and g) mixtures thereof. In the preferred oil-in-water composition or compositions comprising the present invention, the oil phase comprises from about 5% to about 30%, more preferably from about 10% to about 20%, by weight of that composition. Emulsifiers that may be used in any of the composition or compositions comprising the present invention may be any emulsifiers known in the art for use in water-in-oil or oil-in-water emulsions. Water- in-oil and oil-in-water compositions can be prepared by using an emulsifier or mixture of emulsifiers selected from known cosmetically acceptable emulsifiers which include: a) sesquioleates such as the sorbitan sesquioleate which is available commercially from ICI under the trade name Arlacel 83; b) ethoxylated esters of derivatives of natural oils such as the polyethoxylated ester of hydrogenated castor oil which is available commercially from ICI under the trade name Arlacel 989; c) silicone emulsifiers such as the silicone polyols which are available commercially from Th. Goldschmidt AG under the trade name ABIL WS05 and from Dow Corning under the trade designation Silicone Fluid 3225C; d) fatty acid soaps such as potassium stearate; e) ethoxylated fatty alcohols, such as those which are available commercially from ICI under the trade name Brij and from Croda under the trade name Cithrol GMS A/S; f) sorbitan esters, such as those which are available commercially from Croda under the trade name Crill.; g) ethoxylated sorbitan esters, such as those which are available commercially from ICI under the trade name Tween; h) ethoxylated fatty acid esters such as the ethoxylated stearates, which are available commercially from ICI under the trade name Myrj ; i) ethoxylated mono, di, and triglycerides, such as those which are available commercially from Alfa Chemicals under the trade name Labrafil; j) ethoxylated fatty acids, such as those which are available commercially from Alfa Chemicals under the trade name Tefose; k) anionic emulsifiers such as anionic esters of mono and di glycerides available commercially from Grindsted Products Ltd under the trade name Grindtek CA-P (which is not included in any composition or compositions that contain an iron salt or salts) ; and 1) mixtures thereof. The amount of ' emulsifier optionally present in the water-in-oil compositions or compositions comprising the present invention is preferably in the range from about 0.1% to about 20% by weight of that composition. The amount of emulsifier optionally present in the oil-in- water composition or compositions comprising the present invention is preferably in the range from about 0.1% to about 20% by weight of that composition. Any of the composition or compositions comprising the present invention may additionally include one or more other component or components which will be well known to those skilled in the art, for example: a) emulsion stabilisers such as stearyl alcohols or cetyl alcohol, or emulsion stabilising salts such as sodium chloride, sodium citrate or magnesium sulphate, preferably in an amount from about 0.1% to about 5% by weight of that composition; b) humectants such as glycerin or 1,3 butylene glycol, preferably in an amount from about 0.1% to about 30% by weight of that composition; c) thickening agents such as hydroxyethyl cellulose or the acrylic acid polymer available commercially from Honeywill and Stein Ltd under the trade name Junlon PW110, preferably in an amount from a trace amount to about 1% by weight of that composition; d) sequestrants such as the tetra sodium ethylene diamine tetra acetate dihydrate available commercially from Rhone Poulenc under the tradename Sequestene NA4, preferably in an amount from a trace amount to about 1% by weight of that composition, sequestrants not being included in any composition or compositions that contain an iron salt or salts; e) anti-oxidants such as α tocopherol, DLα tocopherol acetate or butylated hydroxytoulene, preferably in an amount from a trace amount to about 2%, more preferably from a trace amount to about 1%, by weight of that composition; f) emollients such as mineral oil, polymethylsiloxane, sweet almond oil, petroleum jelly, isopropyl myristate or triglycerides of fatty acids (for example lauric triglyceride, capric/caprylic triglyceride, or the mixed triglycerides available commercially from Huls UK Ltd under the trade name Miglyol 810), preferably in an amount from about 0.1% to about 30% by weight of that composition; g) moisturisers such as D-panthenol, preferably in an amount from a trace amount to about 1% by weight of that composition; h) agents for adjusting pH such as sodium citrate, potassium hydroxide or citric acid monohydrate, preferably in an amount from a trace amount to about 1% by weight of that composition; i) film formers to assist spreading on the surface of the skin, such as alkylated polyvinylpyrrolidones, preferably in an amount from a trace amount to about 1% by weight of that composition; j) preservatives such as bronopol, sodium dehydroacetate, isothiazolone or diazolidinylurea, preferably in an amount from a trace amount to about 1% by weight of that composition; k) perfumes and colouring; and 1) mixtures thereof. The present invention further provides a method of applying an artificial tanning product to an area of skin comprising the steps of: a) applying to the skin area a composition comprising one or more iron salt or salts; b) applying to the skin area a tanning composition comprising a cosmetically effective amount of dihydroxyacetone as an artificial tanning agent. The steps of the method of the present invention may be performed substantially simultaneously, or sequentially in any order. If the steps are substantially simultaneous, then the iron salt composition and the tanning composition may be a single composition. If the steps are sequential then it is particularly preferred that the iron salt composition is applied prior to the tanning composition. In this preferred method, the iron salt composition advantageously comprises a moisturiser as it has been found that application of a moisturiser prior to application of the tanning composition aids production of an even skin colour. The iron salt composition used in the method of the present invention may comprise any composition comprising an iron salt or salts described herein. Similarly, the tanning composition used in the method of the present invention, may comprise any composition comprising DHA described herein. The invention will now be illustrated by the following non-limiting examples. Where results for a control experiment are also listed in an example, this control experiment was carried out identically to the procedure indicated below for that example using the same proportions of the same ingredients, in the composition or compositions of that example except that the iron salt or salts were removed. Various trade names and the like known to those skilled in the art are used to describe ingredients used in the compositions listed below. For convenience the chemical composition of these ingredients will now be described. Steareth 2 is a polyethylene glycol stearyl alcohol ether having an average of 2 ethylene oxide units per molecule available commercially from ICI under the trade mark Brij 72®; Steareth 21 is a polyethylene glycol stearyl alcohol ether having an average of 21 ethylene oxide units per molecule available commercially from ICI under the trade mark Brij 721® ; Grindtek CA-P is a hydrogenerated palm oil glyceride available commercially from Grinsted Products Ltd; Miglycol 812 is a mixed triglyceride of standard Cg to C- ] _2 acids available commercially from Huls UK Ltd; Silicone fluid Flll/300 is a polydimethylsiloxane available commercially from Dow Corning; Junlon PWllO is an acrylic acid polymer available commercially from Honeywill and Stein Ltd; Sequestrene NA4 is a tetra sodium ethylene diamine tetra acetate dihydrate available commercially from Rhone Poulenc; PEG 20 stearate is a polyethylene glycol stearate having an average of 20 ethylene oxide units per molecule; PEG 7 glycerol cocoate is a polyethylene glycol glycerol cocoate having an average of 7 ethylene oxide units per molecule; Ceteth 20 is a polyethylene glycol cetyl alcohol ether having an average of 20 ethylene oxide units per molecule; Silicone fluid 20cs is a silicone polyol emulsifier; and Silicone fluid lOOOcs is a silicone polyol emulsifier. Example 1 Compositions A) Iron salt composition An iron salt composition for use as a pre- moisturiser containing the following ingredients was prepared as outlined below:- Ingredient % w/w Ferrous giuconate (DHA enhancer) 2.0 Hydroxy ethyl cellulose (thickener) 0.25 Glycerol (humectant) 4.0 1,3 Butylene glycol (humectant) 4.0 Steareth 2 (water-in-oil emulsifier) 2.0 Steareth 21 (oil-in-water emulsifier) 1.0 Light liquid paraffin (emollient) 10.0 Polydi ethylsiloxane (emollient) 2.0 Stearyl alcohol (emulsion stabiliser) 2.3 Glyceryl monostearin (water-in-oil emulsifier) 3.0 DLOC tocopherol acetate (anti-oxidant) qs ■ Preservative qs Perfume qs Purified water to 100 The water soluble ingredients are mixed together and heated to 70°C. The thickener is added to the water phase ingredients using a high shear mixer, followed by the iron salt. The oil soluble ingredients are combined in a separate vessel, heated to 70°C and then added to the water phase mixture using a high shear mixer. The combined mixture is then mixed using the high shear mixer for a further 10 minutes, after which the mixture is allowed to cool to room temperature and preservative and perfume were added as desired. B) DHA-tanning composition An artificial tanning cream comprising DHA to be used in conjunction with the iron composition prepared above was prepared from the following ingredients in the method described below:- Ingredient % w/w Dihydroxyacetone (tanning agent) 4 Grindtek CA-P (oil-in-water emulsifier) 2.5 Miglyol 812 (emollient) 3 DL-α tocopherol acetate (anti-oxidant) 0.2 Almond oil (emollient) 2.0 Glycerin BP (humectant) 4.0 Silicone Fluid Flll/300 (emollient) 1 Light liquid paraffin (emollient) 3 . . 5 Cetyl Alcohol (emulsion stabiliser) 1 Junlon PWllO (thickener) 0 . , 1 White soft paraffin BP (emollient) 1 . , 5 Sodium citrate (pH adjusting agent) 0 . , 25 Sequestrene NA4 (sequestrant) 0 . . 02 Potassium hydroxide (pH adjusting agent) 0 . , 02 Citric Acid (pH adjusting agent) 0 . , 01 Butylated hydroxy toluene (anti-oxidant) 0 . , 01 Perfume 0 . , 29 Preservative qs Purified water to 100 The water soluble ingredients are mixed together and heated to 70°C. The thickening agent is added to the water phase ingredients using a high shear mixer followed by the pH adjusting agents to keep the pH to about 3. The oil soluble ingredients are combined in a separate vessel, heated to 70°C and then added to the water phase mixture using a high shear mixer. The combined mixture is mixed using the high shear mixer for a further 10 minutes, after which the mixture is allowed to cool to room temperature. The DHA was added (and preservative if desired) and the pH of the mixture was adjusted if necessary. Results Both colour and intensity of the skin of human volunteers before and after treatment were measured using a Minolta Chromameter (Model CR-200) as below. A square test area (40 mm x 40 mm) was marked on the forearm of a volunteer and the surface reflectance of that area was measured using the Minolta Chromameter. 40μl of the iron composition above was then applied to the test area and rubbed into the skin with a glass rod and left for 5 minutes to dry. Then 40μl of the tanning composition above was rubbed into the test area in a similar manner and left to dry for 10 minutes, after which the surface reflectance of the test area was measured again. The amount of light reflected, which is detected by the chromameter, gives a quantitative indication of skin colour, which is recorded as 'L', 'a' and 'b' values. The 'L' value gives a quantitative indication of the darkness of the skin, with a lower value indicating darker. The 'a' value gives a quantitative indication of the amount of red or green present in the skin, with a higher value indicating more red. The 'b' value gives a quantitative indication of the amount of blue or yellow present in the skin with a higher value indicating more yellow. 'L' value 'a' value 'b' value Example 1 67.9 6.5 17.9 Control 67.5 7.7 17.5 Example 2 Compositions Iron salt composition and DHA tanning composition were prepared and used as described in Example 1, with the exception that the iron salt composition contained 2% of ferric nitrate by weight of the composition instead of 2% of ferrous giuconate. Results The results of the Minolta colour test are tabulated below: 'L' value 'a' value 'b' value Example 2 65.3 9.1 13.6 Control 65.8 8.9 15.0 Examples 3 and 4 Iron salt compositions and DHA tanning compositions were prepared as described in Examples 1 and 2 respectively, with the addition of 2% w/w α-tocopherol as an anti-oxidant/deodorant to each composition. The compositions of Examples 3 and 4 when used as described in Example 1 produced a similar improvement in tan colour and intensity compared to control compositions as described above for Examples 1 and 2. Some other formulations which may be used as DHA tanning compositions of the present invention are given below: Self Tan Cream 1 Ingredient % w/w Dihydroxyacetone (tanning agent) 4.0 Octyl Methoxycinnamate (sunscreening agent) 1.0 PEG 20 Stearate (emulsifier) 1.3 Cetearyl alcohol (emulsion stabiliser) 2.3 Cetyl alcohol (emulsion stabiliser) 1.0 Liquid Paraffin (emollient) 1.6 Preservative and Perfume qs • Purified water to 100 II) Self Tan Cream 2 Ingredient % w/w Dihydroxyacetone (tanning agent) 4.0 Polyvinylpyrrolidone (PVP) Copolymer 2.0 (film former) Mixed Triglycerides (emollient) 4.0 1,3 Butylene Glycol (humectant) 5.0 Ethoxylated Stearyl Alcohol (emulsifier) 1.5 Cetearyl alcohol (emulsion stabiliser) 2.5 PEG 7 Glyceryl Cocoate (emulsion stabiliser) 1.5 Xanthan Gum (emollient) 0.3 Glycerol (humectant) 2.5 Carboxymethyl Cellulose (thickener) 0.4 White Soft Paraffin (emollient) 2.0 Ceteth 20 (emulsifier) 0.9 Cocoamidopropyl betaine (emulsifier) 2.0 Preservative, Colour and Perfume qs Purified water to 100 III) Tan Maintainer Ingredient % w/w Dihydroxyacetone (tanning agent) 1.2 Alpha bisabolol (anti-phlogistic) 0.1 Glycerate/methacrylic acid polymer (emollient) 2.0 D Panthenol (moisturiser) 0.6 Cetearyl Isononate (emulsifier) 2.0 Hydrogenated Palm Oil Glycerides Citrate 2.0 (emulsifier) Silicone Fluid 20cs (emollient) 2.0 1,3 Butylene Glycol (humectant) 4.0 Arachidyl Propionate (emulsifier) 1.0 Cetyl alcohol (emulsion stabiliser) 2.0 Theobroma Oil (emollient) 1.0 Acrylic Acid Copolymer (thickener) 0.2 Liquid Paraffin (emollient) 4.6 Allantoin (dermatological agent) 0.2 White Soft Paraffin (emollient) 2.0 Glycerol (humectant) 0.8 Potassium Hydroxide (pH adjuster) 0.07 Preservative, Colour and Perfume qs Purified water to 100 IV) Sunscreen with DHA Ingredients % w/w Dihydroxyacetone (tanning agent) 0.5 Butyl methoxydibenzoyl methane 3.0 (sunscreening agent) Octyl methoxycinnamate (sunscreening agent) 7.3 Benzophenone (sunscreening agent) 2.0 Cetearyl Isononate (emulsifier) 9.2 Glycerine esters (humectant) 5.4 Microcrystalline wax (thickener) 3.0 Acrylic acid copolymer (thickener) 0.5 Silicone Fluid lOOOcs (emollient) 5.0 1,3 Butylene Glycol (humectant) 4.9 Cetyl Alcohol (emulsion stabiliser) 1.5 Ceteareth Stearate (emulsifier) 1.0 Almond Oil (emollient) 0.5 Tetrahydroxypropyl ethylenediamine 1.2 (sequestrant) Preservative, Perfume and Antioxidant qs Purified water to 100 V) Sun Lotion with DHA Ingredients % w/w Dihydroxyacetone (tanning agent) 0.5 Butyl Methoxydibenzoyl methane 1.2 (sunscreening agent) Benzophenone (sunscreening agent) 2.0 Cetearyl Isononate (emulsifier) 9.7 Glycerine esters (humectant) 5.4 Silicone Fluid lOOOcs (emollient) 5.0 Microcrystalline wax (thickener) 2.0 1,3 Butylene Glycol (humectant) 4.9 Cetyl alcohol (emulsion stabiliser) 0.3 Ceteareth stearate (emulsifier) 1.0 Acrylic acid copolymer (thickener) 0.4 Liquid Paraffin (emollient) 8.0 Tetrahydroxypropyl ethylenediamine 1.0 (sequestrant) Almond Oil (emollient) 0.5 Preservative, Perfume and Antioxidant qs Purified water to 100

Claims: CLAIMS 1. An artificial tanning product comprising one or more compositions containing, separately or together, a cosmetically effective amount of dihydroxyacetone as an artificial tanning agent, and one or more iron salt or salts. 2. A product as claimed in claim 1, in which the iron salt or salts are present in one or more of the compositions in an amount from about 0.1% to about 20% by weight of that composition. 3. A product as claimed in either preceding claim, in which the iron salt or salts are present in one or more of the compositions in an amount from about 0.5% to about 10% by weight of that composition. 4. A product as claimed in any preceding claim, in which the iron salt or salts are present in one or more of the compositions in an amount from about 1% to about 5% by weight of that composition. 5. A product as claimed in any preceding claim, in which the iron salt or salts are selected from nitrate, giuconate and citrate. 6. A product as claimed in claim 5, in which the iron salt or salts are ferric nitrate and/or ferric citrate. 7. A product as claimed in any preceding claim, which comprises a single composition. 8. A product as claimed in any of claims 1-6, in which comprises two or more compositions packaged in the form of a pack of two or more parts . 9. A product as claimed in any of claims 1 to 8, which one or more of the compositions comprising an iron salt or salt further comprises a moisturiser. 10. A product substantially as described herein with reference to the examples . 11. A method of application of an artificial tanning product to an area of skin comprising the steps of : - (a) applying to the skin area, a composition comprising one or more iron salt or salts; (b) applying to the skin area a tanning composition comprising a cosmetically effective amount of dihydroxyacetone as an artificial tanning agent. 12. A method as claimed in claim 11, in which the iron salt composition comprises any composition comprising iron salt or salts which is described in any of claims 1 to 10. 13. A method as claimed in either of claims 11 or 12, in which the tanning composition comprises any composition comprising dihydroxyacetone which is described in any of claims 1 to 10. 14. A method as claimed in any of claims 11 to 13, in which the tanning composition is applied after the iron salt composition. 15. A method as claimed in any of claims 11 to 13, in which the tanning composition and iron salt composition are applied substantially simultaneously. 16. A method as claimed in claim 15, in which the iron salt composition and the tanning composition together form a single composition.

Inventors: LINNINGTON HELEN LOUISE, SHEARD CHRISTINE, LINNINGTON, HELEN, LOUISE, SHEARD, CHRISTINE
Applicants: BOOTS CO PLC, LINNINGTON HELEN LOUISE, SHEARD CHRISTINE, LINNINGTON, HELEN, LOUISE, SHEARD, CHRISTINE, THE BOOTS COMPANY PLC
Application year: 1994
Main classification: A61K7
IPC codes: A61K8, A61Q17, A61Q19